Insect repellent compositions



Patented 7,

I w s STATES PAT-EN it: I p

T OFFICE msnor narnLLaNT co urosrrross Howard a. Jones and Bernardvi'lravis, simian,

Fla assignora to the United States of America I as represented by the Secretary 01' Agriculture No Drawing. Application March s, 1945,

Serial No. 580,792

10 Claims. (01. 167-30) (Granted under the act ,of March 3,

amended April 30, 1928; 370 0. G. 757) their essential active ingredients compounds of the class of alkoxyphenylalkyl alcohols, having the general formula wherein R. is an alkyl group and R. is a divalent radical having the general formula CnHi-m'where n is an integer of at least one, such as the methylene radical (4-CHn--), the cthylidene radical (CI-13011:), the ethylene radical (--CHaCHa the trimethylene' radical (-CI-IzCHzCHa-L etc., and where the relative positions of R and R'OH are other than the meta position, that is, R0 and R'OH are in either the ortho or the para positions to each other. For example, such come pounds of this class as p-methoxybenzyl alcohol, p-ethoxybenzyl alcohol, p-n-propoxybenzyl alcohol, l- (p-methoxyphenyl) ethanol, 2- (p-methoxyphenyl) ethanol, 3- (p-methoxyphenyl) -n-propanol, and o-methoxybenzyl alcohol. have been found to repel insects for considerable periods of time and are especially effective in repelling certain types of Aedes mosquitoes.

These alkoxyphenylalkyl alcohols may be used in numerous ways to repel insects. They may be applied to the area from which the insects are to be repelled, such as to the exposed parts oi the body or to clothing, either in their undiluted form or in suitable inert carriers, such as solvents like mineral oils, vegetable oils and various alcohols, etc. They may also be incorporated into inert powders to obtain a paste or cream for application to the skin and may also be applied in the form of an aqueous emulsion, particularly in the and chigger attachments. For example, when applied to impregnate clothing, p-methoxybenzyl alcohol has been found to be very effective in preventing the attachment of Trombiculidae (chiggers). Furthermore, in any of the aforementioned modes of application, mixtures or blends of individual alkonphenylalkyl alcohols may be treatment of clothing to prevent mosquito bites employed and they may also be mixed with other khown insect repellents, such as dimethyl phthala e.

The compositions of this invention have been tested by the standard method employed in evaluating insect repellent compositions. 'In this method one-fourth teaspoonful of the material to be tested is applied to the forearm from wrist to elbow and the arm then exposed to a large number of hungry mosquitoes or other biting insects, the time elapsing to the first bite being recorded. This "test is of a practical nature and gives results that are highly indicative of the insect repellent in actual field use.

The following table illustrates the results ob-' tained against Aedes aegupti and Anopheles "quadrimaculatus as examples of insects against which the invention is applicable, using the above method and utilizing p-methoxyben'zyl alcohol, p-ethoxybenzyl alcohol, p-n-propoxybenzyl alcohol, 1- (p-methoxyphenyl) ethanol, 2- (p-methoxyphenvDethanol, 3-(D-methoxyphenyl) n-propanol, and o-methoxybenzyl alcohol in undiluted form and diluted with inertcarriers.

In addition the foregoing examples shown in the above table, a large number of'tests were 'conducted against natural populations of 'Aedes taeniorhunchus under actual field conditions. It was found that the alkoxyphenylalkyl alcohols ave good repellent action, for example, p-meth oxybenzyl alcohol giving repellent 'action similar to that shown in the above table.

The high repellent value of o-methoxybenzyl alcohol is quite unexpected and could not have been predicted from the results obtained with pmethoxybenzyl alcohol and other p-alkoxyphenlllalkylalcohois.

- radical having the general formula CnHfln,

.wherein R is an It has been found that while p-methoirybenzyl alcohol causes a slight irritation of sensitive skin if applied in full strength, other alkoxyphenylalkyl alcohols, such as p-n-propoxybenzyl alcohol, l-(p-methoxyphenyl) ethanol, 2-(p-methoxyphenyllethanol, 3- (p-methoxyphenyl) -n-propano1, o-methoxybenzyl alcohol, cause no irritation. Having thus described our invention, what is claimed is:

1. An insect repellent composition comprising a compound of the general formula wherein R is an alkyl group andR is a divalent radical having the general formula CnHin, where n is an integer of at least one, and R and R'OH are in the ortho position to each other, incorporated ina carrier selected from the group consisting of a vegetable oil, an inert powder, and

' 'water.

2. An insect repellent composition comprising a compound of the general formula R0.C6H4.R'0H

wherein R is an alkyl group and R where n is an integer of at least one, and R0 and R'OH are in the para position to each other, incorporated in a carrier selectedwfrom the group consisting of a vegetable oil, an inert powder, and

water.

3. An insect repellent composition comprising 'l-(p-methoxyphenyDethanol incorporated in a carrierwselected from ;the group consisting of a vegetable oil, an inert powder, and water.

4. An insect repellent composition comprising Z-(p-methoxypherlyl) ethanol incorporated in a carrier selected from the group consisting of a vegetable oil, an inert powder, and water.

5. An insect repellent composition comprising o-methoxybenzylalcohoi incorporated in a carrier selected from the group consisting of a vegetable 011, an inert powder, and water.

6. An insect repellent composition comprising a compound of the general formula wherein R is an alkyl group and R is a divalent radical having the general formula CnHfln, where n is an integer of at least one, and R0 and R'OH are in the ortho position to each other, incorporated in an inert powder to form a paste.

7. An insect repellent composition comprising a compound of the general formula is a divalent wherein R is an alkyl group and R' is a divalent radical having the general formula CnHQn, where n is an integer of at least one, andiR/O and R'OH are in the ortho position to each other.

9. A method of repelling insects comprising applying to the area from which the insects are to be repelled an insect repellent composition containing as its essential active ingredient a compound of the general formula wherein R is an alkyl group and R' is a divalent radical having the general formula CnHfln, where n is an integer of at least one, and R0 and R'OH are in the para position to each other.

10. A method of repelling insects comprising applying to the area from which the insects are to be repelled an insect repellent composition containing l-(p-methoxyphenyl)ethanol as its essential active ingredient.

11. A method of repelling insects comprising applying to the area from which the insects are to be repelled an insect repellent composition containing Z-(p-methoxyphenyl) ethanol as its essential active ingredient.

12. A method of repelling insects comprising applying to the area'from which the insects are to be repelled an insect repellent composition containing o-methoxybenzyl alcohol as its essential active ingredient.

13. An insect repellent composition comprising a compound of the general formula wherein R is an alkyl group and R is a divalent radicalhaving the general formula CnH2n,.where 1i is an inte er of "at least one, and the relative positions of R0 and R'OH are other than the meta position incorporated in a carrier selected from the group consisting of a vegetable oil, an inert powder, and water.

14. A method of repelling insects comprising applying to the area from which the insects are 1 to be repelled an insect repellent composition containing as its essential active ingredient a compound of the general formula wherein R is an alkyl group and R is a divalent radical having the general formula CnHZn, where n is an integer of at least one, and the relative positions of R0 and R'OH are other than the meta position.

15. An insect repellent composition comprising a p-methoxyphenyl ethanol incorporated in a carrier selected from the group consisting of a vegetable oil, an inert powder, and water.

16. A method'of repelling insects comprising applying to the area from which the insects are to be repelled an insect repellent composition containing a p-methoxyphenyl ethanol as its essential active ingredient,

HOWARD A. JONES. BERNARD V. TRAVIS. 

